Wind Advisory 12, NWS Flagstaff, AZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
317 PM MST Sun May 19 2019

.SYNOPSIS...A strong late season low pressure system will
continue to bring periods of rain and high elevation snow to
northern Arizona through Monday. Another low is forecast to impact
the area by late Tuesday, with more cold, wet and windy weather
through much of next work week.

&&

.DISCUSSION...Current satellite imagery shows an upper-low
centered over Lake County, CA. This low will continue to dive
southeastward today, making it into far northwest Arizona by
early Monday morning. Ahead of the low, strong winds have occurred
across northern Arizona this afternoon. Frequent southwest wind
gusts into the 40 to 50 mph range have been observed for areas
along and north for the Mogollon Rim from Flagstaff eastward. A
Wind Advisory remains in effect for most areas through 6 PM MST.
In addition, radar shows showers across portions of Coconino and
Yavapai Counties. Some of the stronger showers are producing
graupel, which may produce hazardous driving conditions if they
accumulate on area roadways. These showers will slowly expand
eastward through the evening and overnight hours.

For tonight, wind speeds will decrease at most places, but gusty
downslope winds will persist at areas to the northeast of higher
terrain. Snow levels will drop as cold air filters into the area
with the advancing low. By Monday morning, snow levels are
forecast to be around 6000 feet at most places. Snow accumulations
are expected to be light, although an inch or two of accumulating
snow is possible from the North Rim of the Grand Canyon to Jacob
Lake.

On Monday, the low moves across the state. Current model data
suggests 700mb temps within the core of this unusually cold low
will be between -6C to -7C. This will lead to significant
instability and numerous convective showers. Some areas will
likely see temporary snow accumulations with the passing of the
heavier snow showers, down to about 6000 feet or so. The
greatest impact on Monday will be locally limited visibility in
snow showers, and the possibility of hazardous driving if the
snow is heavy enough to accumulate.

The low moves east on Tuesday, which may bring a brief downtrend
in shower activity. However, another round of strong southwest
wind gusts into the 40 to 50 mph range is forecast ahead of a
second weather system due to sweep across the area beginning late
Tuesday. More rain and mountain snow is possible, especially on
Wednesday. Some shower activity may continue into Thursday.

From Friday into next weekend, northern Arizona remains in an
active weather pattern, but model guidance is trending drier.

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.AVIATION...For the 00Z package... Expect gusty south to southwest
winds at 20-30G35-45 kts decreasing after 03Z Mon. Conditions will
remain gusty through the overnight for areas to the northeast of
high terrain. Thunderstorms and mountain snow showers remain
possible, mainly west of a line from KPRC to KPGA through 02z.
Showers and thunderstorms will then gradually spread to the east
through the evening and into the overnight. Expect MVFR/IFR
conditions with gusty and erratic winds possible near thunderstorms
and heavier showers. Aviation discussion not updated for TAF
amendments.

&&

.FIRE WEATHER...Showers, mountain snow, and scattered thunderstorms
will continue through Monday evening. Snow levels decrease to around
6000 ft by Monday morning. Winds will remain breezy northeast of
high terrain overnight Sunday into Monday. Chance for showers mainly
north of I-40 and gusty southwest winds return on Tuesday.

Wednesday through Friday...The trend of below normal temperatures,
gusty winds and additional chances of precipitation each day will
continue through Thursday. Dry conditions will return Friday with
cool temperatures remaining.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...Wind Advisory until 6 PM MST
this evening FOR AZZ004>017-038>040.

&&

PUBLIC...RR
AVIATION...ET
FIRE WEATHER...ET

For Northern Arizona weather information visit
weather.gov/flagstaff